Much attention has been given in recent years to the development of systems that would permit the electronic display of prices to customers in self-service stores at the shelves where goods are kept. Such a system, if commercially viable, offers many advantages over the manual posting of prices. Chief among those advantages is that one may have a high degree of confidence that the price computed by the scanner at the checkout counter will match the price that was provided to the customer at the shelf. Another salient advantage is that price changes, due, for example, to sale markdown or price increase or decrease, may be promulgated to the shelf automatically and reliably.
The store in which an electronic price display system is to be installed will typically have a number of gondolas, each having shelves on two sides. The gondolas define aisles in the store. Installation of the electronic price display system will typically call for mounting a rail on the outside edge of each shelf. Each shelf is typically four feet in length, so the corresponding rails are typically four feet in length as well. The shelves extend horizontally. Each rail contains power and data wiring (called a power and data bus), and the power and data buses of the rails are combined and brought together at gondola controllers. Signals from the gondola controllers are combined and communicated to a central computer (called a host). Attached to each rail are a number of electronic price display labels. Each display connects to the power and data bus, and has a liquid-crystal display (LCD). Electronic circuitry in the label responds to messages on the bus by driving the LCD appropriately.
To implement a price change, the host sends messages to the gondola controllers, which in turn communicate corresponding messages to the price display labels. Each label is separately addressable which permits the host to change the information on a single label, if desired, among the several tens of thousands of labels in the store. The manner of communication between host and labels can be that described in U.S. Pat. No. 5,172,314.
Power is distributed to the labels via conductors. Protection against inadvertent shorts in the power distribution wiring may be provided as described in copending U.S. application Ser. No. 07/757,259.
The features of the electronic price display system described herein are largely mechanical in nature. The electronic and software aspects of the electronic price display system may be selected from among those described in copending U.S. application Ser. Nos. 07/757,260, 07/757,675, and 07/876,198. The manner in which labels are installed to and removed from a rail as described herein differs in several respects from that described in copending U.S. patent application Ser. No. 07/965,877.
As will be appreciated, a typical hardware complement for a grocery store might be as follows: 1 central computer (host); eight gondola controllers, 2000 four-foot rail sections, and 30,000 label displays. Cost optimization greatly favors reducing the unit cost of the labels and the rails, even if this increases the unit cost of the host or gondola controllers.
In tension with the goal of cost optimization is the requirement that the system be highly reliable. Reliability requires mechanical and electrical integrity for the labels and rails. While a number of conditions affecting reliability in other settings, such as temperature, humidity, and corrosiveness of the atmosphere, tend to be well controlled in most stores, an electronic price display system for use in a retail store is exposed to other risks. The aisles of a grocery store, for example, present hostile conditions such as the predations of shopping carts, small children, and wagons used in transporting goods for restocking. Although a number of investigators have set up experimental electronic price display systems in actual retail stores, many of the experiments have been less than successful, leading to abandonment of a number of label and rail mechanical configurations that have proven too fragile for the store conditions. With many electronic price display systems it is all too easy for a shopping cart to slam into a label, for example, knocking the label off the rail or disrupting the label's electrical contact with the rail. The latter possibility illustrates that a rail system must provide not only mechanical integrity but electrical integrity. It is undesirable that a rail be susceptible to changes in shape that would reduce the electrical integrity of the label's connection thereto.
Yet another competing factor in system design is the requirement that the initial installation of the system be quick. Labor inputs for system installation call for relatively skilled technicians, whose time should be efficiently used. When the rails are attached to the shelves, fasteners such as screws are typically used. It is desirable that no more fasteners be used than are necessary to keep the rail reliably on the shelf. The system has to integrate itself gracefully with shelf mechanical configurations commonly used in stores, such as the standard "C" channels found at the outside (near) edge of most shelves in North America.
Another concern is that addition of rails to a store should not interfere with existing store functions. One obvious example is that if the rail has greater vertical extent than the "C" channel, it will make the shelf unusable for some products the tallness of which had barely permitted placement on the shelf before the rail was installed. Another example is that a store employee will sometimes restock goods by propping one edge of the corrugated cardboard case or carton against the "C" channel, holding the case in place by pressure applied by the abdomen to the other edge of the carton. This increases the stocking efficiency of the employee. During such so-called "belly stocking" both hands are free for lifting goods from the case onto the shelf. It would be undesirable if the rail to be installed to a shelf did not provide a face accommodating belly stocking.
Still another competing factor in system design is the requirement that additions and changes to the price display system be straightforward for authorized store personnel; despite this the system should actively discourage unauthorized tampering and modification. Since the display labels are nonzero in cost, it is desirable that the system function so as to minimize theft or other loss of the labels themselves.
Finally, system design must answer to aesthetic values. It is desirable that the rail itself be relatively unobtrusive, so that each label is all the more easily identified and located. If fasteners such as screws are used to secure the rails to the shelves, it would be preferable that the screw heads not be visible. Where a store has an intentional color scheme it would be desirable that the rail configuration permit style elements to conform to the color scheme.
From the foregoing discussion it will be appreciated that it is no easy task to optimize all the above-mentioned aspects of the design of a price display system. Yet to be commercially viable a price display system must offer at least a moderate degree of success on nearly every measure. As was mentioned above, the lack of commercial success in any of numerous attempted electronic price display systems is attributable at least in part to shortcomings in one or more of the above aspects.